Adsorption of copper ions from wastewater using activated carbon derived from Centella asiatica leaves

Abstract

This work focused on studying the adsorption of Cu(II) from aqueous solutions by acid activated carbon prepared from Centella asiatica (CA) leaves. Under batch mode, the performance of activated CA in the removal of Cu2+ ions is assessed with a focus on operational parameters such as pH (2 to 9), activated CA dose (25 to 150 mg/g), initial Cu2+ ions concentration (10 to 50mg/L), contact time (10 to 90min) and temperature (30 to 60°C). Adsorption data are tested with isotherms (Langmuir and Freundlich) and kinetic models (pseudo-first order and pseudosecond order). Thermodynamic parameters (ΔGo, ΔHo and ΔSo) are computed. The following results are optimized under batch mode: initial concentration of 10 mg/L, activated CA dose of 100 mg/L, contact time of 90 min, pH of 6 and temperature of 300C. The adsorption isotherm fits well with Langmuir model. The adsorption is well controlled by the pseudo-second order. The computed thermodynamic parameters signified the reaction process’s feasibility, endothermicity, spontaneity and physisorption. The results show that activated CA can effectively remove Cu2+ ions from aqueous solutions.